Bladder Tumors

Key Points

Most bladder tumors are transitional cell carcinomas

Some tumors are benign and are very treatable with surgery

Malignant tumors generally are treated with palliative measures:

Chemotherapy

urethra stenting

Cystostomy tube

Antibiotics

Anti-inflammatories

Anatomy

The urinary system is made of the kidneys, the tubes (ureters) that pass urine from the kidneys to the bladder, the bladder which is a reservoir for urine, and the urethra, which is the tube that drains urine from the bladder to the outside. The urethra in males is fairly long and a portion of it runs through the tissue of the penis. In dogs the penis has a bone (os penis) that surrounds the urethra for part of its length. The diameter of the urethra narrows as it passes through the os penis.

Introduction

Bladder cancer is the most tumor of the urinary tract and comprises about 1% of all cancers in dogs and cats. Dogs develop this type of tumor more often than cats. Risk factors include nitrosamines, insecticide dips, cyclophosphamide, Sentinil, obesity, and living in an industrial location.

Bladder tumors are usually malaignant with only 3% of tumors being benign. Malignant tumors: transitional cell carcinoma is most commonly diagnosed, however other reported tumor types include squamous cell carcinoma, adenocarcinoma, fibrosarcoma, leiomyosarcoma and hemangiosarcoma, botryoid rhabdomyosarcoma. Benign tumors: fibromas, leiomyomas, and papillomas. Noncancerous growths: pyogranulomatous or polypoid cystitis. Most malignant bladder tumors invade the entire thickness of the bladder and diffusely involve the bladder at the time of diagnosis. At the time of initial presentation, about 50% of the patients have evidence of spread of the tumor to regional lymph nodes, pelvic and lumbar vertebrae and lungs; less commonly they spread to the liver and lymph nodes in the chest and abdomen (sternal and mesenteric nodes). At the time of autopsy, 75% of the patients have evidence of metastasis of bladder tumors.

Clincial signs

In most cases, signs of a bladder tumor mimic signs seen with bladder infection and include bloody urine, incontinence, frequent urination, and straining to urinate. Inability to pass urine may becaused by obstruction of the urethra (tube that passes urine from the bladder to the outside) and this is considered an emergency.

Clinical signs of spread of the tumor to the back bones may include crying out in pain, reluctance to jump on elevated surfaces, sensitivity when the back is palpated and lameness/dysfuntion of hindlimb function (due to compression of nerves or spinal cord).

Clinical signs of advanced spread of the tumor to other parts of the body may include weight loss, loss of appetite, malaise, weakness, vomiting and breathing difficulties.

Diagnosis

A mass in the bladder can be palpated by the veterinarian in only 12% of the cases, but those cases that have spread into the urethra can be diagnosed with digital rectal examation in 23% of the cases (for this reason it is critical for your veterinarian to always perform a digital rectal examination).

Routine blood work including a complete blood count and chemistry profile will not provide a diagnosis of a bladder tumor, however, is important to rule out tumor associated problems such as kidney compromise caused by obstruction ureters (tubes that pass urine from the kidneys to the bladder).

Testing of the urine should include urinalysis, cytology, and urine culture. Another test that can be run on the urine is the bladder tumor antigen test. If this test is negative, there is a very low chance that your pet has bladder cancer. If the test is positive, it does not mean that your pet has bladder cancer, as other disease such as urinary tract infection can give a positive test result.

Chest radiographs (x-rays) are made to rule out spread of tumor to the lungs. Radiographs of the pelvis may reveal spread of the tumor to the pelvic bones or lower spine; nuclear scintigraphy is a more sensitive test to evaluate for spread of cancer to the bones. Radiographs of the limbs are indicated if lameness is present and may show a condition called hypertrophic osteopathy; this condition causes the production of new bone to grow on the lower limb bones as a result of stimulation of the blood supply of the limbs by the bladder tumor.

Urinalysis frequently shows a concurrent bladder infection, but usually does not provide a diagnosis of the tumor

Fine needle aspiration of bladder tumors have been reported to cause spread of the tumor to the abdomen.

Traumatic catheterization technique can be used to collect cells from the tumor to help with making a diagnosis

The diagnosis of a bladder mass is usually based on ultrasound findings. In dogs, most transitional cell carcinomas will be located at the neck of the blader (trigone). In cats, however, this tumor tends to be located in the front of the bladder, but may grow in any region.

Cystoscopy is an excellent tool to help identify the extent and nature of the bladder tumor. Benign masses tend to be located in the front bottom (cranioventral) apsect of the bladder and usually are attached to the bladder by a narrow stalk (see video below right). Masses that are malignant tend to be located in the neck of the bladder. The video below left shows a small cancerous tumor of the bladder.

Treatment and prognosis

In years past, surgery has been recommended in most cases of bladder tumors. In one study that evaluated the effectiveness of surgery alone, the median survival time was 86 days. Surgeons have never been able to achieve clean surgical margins and tumor recurrence is expected in cases of transitional cell carcinoma. For this reason, tumors that are potentially benign, small tumors, and in a location that is easily treated will have surgery. Polyps that are large can be easily and successfully treated with surgery

Radiation therapy has extended life for about 1 year in about 61% of the patients. The side effects (colits etc) can be a major complication with radiation therapy.

The primary treatment for most bladder tumors includes treatment of the bladder infection with antibiotics, chemotherapy to try to stabilized the growth of the tumor or shrink the tumor and a nonsteroidal anti-inflammatory. In one study, Mitoxantron and doxorubicin demonstrated median survival time to 259 days. In two studies, cisplatin (a chemotherapy agent) resulted in a partial response in 39 to 79% of the dogs with median survival times of 130 to 180 days. A sister drug, carboplatin did not show any value for transitional cell carcioma in dogs. In another study, carboplatin and prioxicam resulted in median survival time of 161 days. Remission was achieved in 40% of the cases. Due to the toxic side effects seen in many animals, the investigators do not recommend this chemotherapy regimen for TCC. In another study CO2 laser ablation of the visible tumor and the entire lining of the bladder followed by treatment with mitoxantrone resulted in a median disease free interval of 200 days and median survival was 299 days. Although the survival times were similar to chemotherapy protocols alone, the period of time in which the patients had no signs of disease was significantly longer.

Prioxicam, a nonsteroidal anti-inflammatory mediation can provide relief of bladder pain by reducing inflammation and potentially an anti-tumor mechanism. In a study of 34 patients using this drug alone, 2 dogs had complete remission, 4 had partial remission and 18 had stabilization of the size of the tumor; the median survival was 181 days. Some oncologists will prescribe misoprostol when piroxicam is used to help prevent gastrointestinal ulcers and kidney damage.

Palliative stenting of the urethra (for dogs that have obstruction to urine flow due to tumor) resulted in good to excellent clincal function (no incontinence or urinary retention with ability to freely urinate in 3 of 4 females and 6 of 8 males. Unfortunately, the median survival time was only 20 days in this series of cases, but case selection may have influenced the outcome.

Many dogs will not have a bowel movement for the first 4 to 5 days after surgery

Reasons that a dog will not have regular bowel movements after surgery include:

The dog has been fasted prior to surgery

Dogs do not eat well during the hospital stay

They frequently do not eat well when they go home

They are fed highly digestible food that produces little stool

Pain medication that contain narcotics (such as morphine, fentanyl patches, and tramadol) can be constipating

If a pet does not have a bowel movement on the 5th day of being home, a stool softener such as metamucil can be fed

Dose of metamucil is 1 tsp per 25 Kg mixed in with each meal (canned dog food); feed immediately after mixing, as the metamucil will gel the food and may make it less palatable

My pet had surgery and will not eat. What can be done?

Dogs

Most pets will not eat their regular dog food after surgery, especially if it is kibble.

Offer a cooked diet having a 1:1 ratio of a protein source and carbohydrate source. The protein source can be any meat (example: chicken breast, turkey breast, lean hamburger) that is low in fat and should be cooked (drain off all fat after the meat has been cooked). The carbohydrate can be pasta, potato or white rice.

Try canned dog food; to enhance the flavor sprinkle a very small amount of garlic powder or chicken or beef broth (Chicken-in-a- MugTM or Beef-in-a-MugTM products)

Try Gerber strained meats for babies such as the chicken, beef, turkey, or veal

Try Hill's A/D diet available at most veterinary hospitals

Hand feeding: place a small amount of food in the mouth so that your dog gets the flavor

Warm the food slightly in a microwave, as the food will be more aromatic; stir the food before feeding and test the temperature on the bottom side of your wrist; it should only be luke warm.

Remember that most pets will not eat the first day or two after they get home from surgery

Cats

Offer smelly foods that contain fish such as tuna or smelly cat foods

Try Gerber strained meats for babies such as the chicken, beef, turkey or veal

Hand feeding: with your finger place a small amount of food on the roof of your cat's mouth; use a syringe to get soft food into the mouth

Warm the food slightly in a microwave as the food will be more aromatic; remember to stir the food before feeding and test the temperature; it should be only luke-warm

Some cats will only eat dry food, try kibble if your cat normally has been fed that food

Petting and stroking your cat frequently will help to stimulate appetite

Remember that most pets will not eat the first day or two after they get home from surgery

Appetite stimulants such as cyproheptadine may be helpful

If your cat refuses to eat anything for 7 days a stomach tube or nasogastric tube should be placed to provide nutrition so that a serious liver problem (hepatic lipidosis) does not develop

My pet is vomiting. What can be done?

The first thing for you to discern is whether your pet is vomiting or regurgitating. Both will result in fluid or food being brought up. Vomiting always will have heaving or retching of the abdomen prior to expulsion of the vomitus. Regurgitation is not associated with heaving and the pet usually just opens the mouth and fluid or food will be expelled. Usually the regurgited material will be clear or brown colored fluid.

Next is to identify the cause of the vomiting or regurgitation.

Causes and treatment of vomiting after surgery

When some pets return home after a stay in the hospital they may drink excessive amounts of water at one time and then vomit; if this appears to be the case, the water should be limited to frequent smaller amounts.

Medications such as antibiotics, narcotics or nonsteroidal anti-inflammatory medication commonly cause vomiting after surgery. In order to see which medication is causing the problem, the administration of each drug should be separated 2 hours apart. Usually the pet will vomit or appear nauseated (drooling and sick look) within 1 hour of administration of the medication that they are sensitive to. The antibiotic in some cases may be changed to a different one, or may be discontinued.

Stomach upset from anesthesia is a potential cause of vomiting and will pass within a couple of days.

An uncommon cause of vomiting after surgery is internal organ failure. Blood testing will confirm this problem. For this reason vomiting should not be ignored if it persists for more than 24 hours.

If your pet had surgery of the bowels or stomach, vomiting is always a concern, as it may indicate that infection of the abdominal cavity, called peritonitis, is present. Do not ignore this sign.

Symptomatic treatment of vomiting involves withholding food for 12 to 24 hours, then introducing small amounts of bland food such as rice and lean cooked hamburger, if your pet does not vomit after that then gradually wean him/her back onto the regular diet after 3 days. In order to decrease the acidity of the stomach, Pepcid AC 0.5 mg/kg can be given by mouth twice daily for 5 days. Metoclopramide and Cerenia are good anti-vomiting medications for dogs and cats. You should always consult a veterinary healthcare professional before administering medication.

Causes and treatment of regurgitation after surgery

The most common cause of regurgitation is reflux of acid from the stomach into the esophagus while your pet is under anesthesia. Acidic fluid from the stomach can cause a chemical burn of the esophagus and result in a bad case of heart burn, called esophagitis. This results in poor motility of the esophagus, therefore water and food will accumulate in this structure. In most cases, esphagitis is self-eliminating and will resolve within two or three days.

If the esophagitis is severe the esophagus may develop one or more strictures. A stricture is a narrowing or stenosis of the esophagus and does not allow passage of food down the esophagus, in regurgitation that lasts longer than one week. This problem should be brought to the attention of your pet's doctor within the first two weeks so that it can be treated by ballooning the stricture (minimally invasive procedure, as it is done with the aide of an endoscope). If an esophageal stricture is chronic surgery is needed.

Symptomatic treatment of regurgitation caused by esophagitis includes feeding bland food, and administering a coating agent (sucralfate) and an acid blocker (omeprazole or other). Consult a veterinary health care professional if the regurgitation continues for more than a couple of days.

How do I know that my dog is in pain following surgery?

Signs of pain include

crying

biting if you get near the surgical site

grimacing (lips are pulled back and the the dog looks anxious)

tragic facial expression

panting

restlessness and unable to sleep; pacing

if abdominal surgery was done the pet will not lie down on the incision, or will continually sit up in spite of appearing very tired

Anti-inflammatories used to control pain: Deramaxx, Rimadyl, Previcox, or Etogesic

If an orthopedic surgery has been done cold packing the surgical site may be helpful

A cold pack may be a pack of frozen peas, crushed ice in a Ziploc bag, or a cold gel pack; place a thin barrier between the skin and the cold pack. An alternative to a cold pack is to freeze water in a styrofoam cup; after frozen cut the bottom of the styrofoam cup out. Cool the surgical site around the incision by rubbing the exposed ice directly on the skin in a circular pattern. Cooling the surgical site helps to numb the area.

How do I know that my cat is in pain following surgery?

Pain is more difficult to assess in cats versus dogs, as signs can be more subtle and they usually do not vocalize when in pain

Signs of pain in a cat include the following:

biting if you get near the surgical site

growling or deep cry

not wanting to eat

hiding and not wanting to be near owner (remember that this could also be caused by the cat just being upset about leaving home and coming back)

What can be done for pain at home for my cat?

Pain medication such as buprenorphine or a Duragesic (fentanyl) patch

Tylenol will kill a cat as they lack abundant glutathione enzyme in the liver

Anti-inflammatories can be used, but the dose is much less than dogs

Is it okay for my pet to lick the incision?

If a dog licks the incision, the healing process may be delayed.

Licking can remove stitches and cause the incision to open

Licking can become a severe habit that is difficult to break

Licking can cause infection as the mouth has many bacteria

Dogs will frequently lick the incision when the owner is not watching such as at night time; if the skin looks red or excoriated the most common cause is from licking.

To stop your pet from licking the following can be tried:

Elizabethan collar can be placed on the neck; this will not help stop your pet from scratching at the region

Cervical collar (bite not collar) is a less awkward device and can be effective at stopping a pet from licking the surgical site

A tee shirt can be used to cover an incision on the chest or front part of the abdomen; gather the waist of the shirt up over the dog's back and wrap an elastic band around this part of the shirt.

A bandage or sock can be used to cover an incision on a limb; fasten the top of the sock to the dog's limb with tape.

Bitter apple can be applied around the incision; many dogs will continue to lick after application of this topical

Bitter Apple and Liquid HeetTM (obtain this from a drugstore...it is used for sore muscles) mixed in a 2:1 ratio can be applied around the skin incision

Antipsychotic medication in some cases is needed

Board-certification by the American College of Veterinary Surgeons

What does it mean?

Four years of advanced training in surgery beyond the Doctor of Veterinary Medicine Degree

Experience in the development of new surgical treatments

Rigorous examination by the American College of Veterinary Surgeons to ensure competency in advanced surgical techniques